I have an area in my garden that I planted some shrubs and trees in which is 19ft by 19ft. Prior to planting I cut the grass in that area down to the lowest. I would like to make this area into a rockery. I have bought a sheet of weed control fabtic which I intend laying in this area. Would it be okay to just lay this over the ground now or do I have to get rid of the grass completely? .
But to answer your question: you can put the fabric down on existing weeds but they might poke out at edges and joints.